Science File / An exploration of issues and trends affecting science, medicine and the environment

Q: Does the Panama Canal allow a mixing of water from the Atlantic and Pacific Oceans? Have any species migrated from one ocean to the other?

A: There is very little mixing of waters between the two oceans at the canal, both because of the three-tiered system of locks that protect Panama’s vulnerable lowlands from flooding and the freshwater lake near the center of the canal. Were it not for the locks and the lake, mixing of the waters would allow free migration of species from one ocean to the other, as has occurred at the sea-level Suez Canal. The opening of that canal has permitted extensive migration of marine life, according to marine biologist J. E. McCosker of the Steinhart Aquarium in San Francisco, leading to the extinction of several native species.